The invention relates to a switching element provided with two electrodes with a semiconducting dielectric therebetween, one electrode comprising a material which forms a Schottky contact with the semiconducting dielectric, with a space charge region of the Schottky contact forming a tunnelling barrier for electrons during operation. The invention also relates to a memory element.
Japanese Patent Application no. 60-182762 discloses a device of the kind mentioned in the opening paragraph with a first electrode of titanium, a dielectric of an n-type semiconducting oxide of tungsten, and a second electrode of iridium. The iridium of the second electrode and the dielectric form a Schottky contact whose space charge region forms the tunnelling barrier in the dielectric for electrons which are transported from the one to the other electrode. The known switching element has a memory which is obtained through ageing or the switching element by means of a voltage across the dielectric. This voltage moves ions through the dielectric. These ions influence the space charge region of the Schottky contact and thus the tunnelling barrier so that switching states arise in which more or less current is allowed through. The switching states are held during a certain period.
The known device described has the disadvantage that a switching state of the switching element is held for a short time only, i.e. no more than a few tens of seconds.